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Finding the Fourth Proportional to 858.16, 1,285.18 and 815.10

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Solution

The fourth proportional to 858.16, 1,285.18 and 815.10 is: 1,220.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.16 : 1,285.18 = 815.10 : x
  2. Step 2: Convert to fraction form
    858.16/1,285.18 = 815.10/x
  3. Step 3: Cross multiply
    858.16x = 1,285.18 × 815.10
  4. Step 4: Simplify right side
    858.16x = 1,047,543.36
  5. Step 5: Solve for x
    x = 1,047,543.36/858.16
  6. Step 6: Final answer
    x = 1,220.68

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.